Conventionally, a silver salt photography type mask for exposure is used for printing an image on photographic paper. In general, the mask used conventionally is the silver halide photosensitive material (for example, Clear QA manufactured by Konica Co.) for that being used in order to view an image while the image is illuminated from the reverse side. This material has a transparent support, and non-image formed portion of this material after development is not-colored and transparent.
However, when the aforementioned silver halide photosensitive material is used, gradation of the obtained image is high. Therefore, illustrations and characters can be excellently printed on photographic paper, however, the quality of a natural image can not be satisfactorily high. For this reason, it is necessary to separately prepare a mask for exposure in which silver halide photosensitive material having a gradation property appropriate for a natural image is used. It is also required that an image printed on photographic paper is close to a designed image.
Furthermore, when silver halide photosensitive material is used for the mask for exposure, this mask for exposure is restricted by the coupling and developing properties of dyes of which color is in accordance with the combination of a coupler and developing agent. Therefore, it is difficult to design a photosensitive material, the irregular absorption of which is small.